1. Field
The present specification relates to monitoring the earphone wearing state of a user wearing headphones that include left and right earphones, as well as to a method of controlling a mobile device according to the wearing state.
2. Description of the Related Art
Typically, headphones are used as an apparatus for the purpose of a user converting an audio signal output from an audio playback apparatus into a sound wave (audible sound), generally to listen to music or other such audio alone. The headphones in this specification are connected to such an audio playback apparatus in a wired or wireless manner, and include stereo types provided with a pair of left and right earphones. An earphone herein refers to the component of headphones worn so as to bring a speaker close to one of the user's ears.
Hitherto, technology providing audio-based navigation to pedestrians wearing headphones has been proposed (see PTL 1). With this technology, the angle of cranial rotation with respect to the direction in which a user is traveling (the front-to-back direction of the user's body) is computed as follows. Namely, established laser range-finding methods are used to detect the shortest distance from the user's left shoulder to the left side of the headphones, and also to detect the shortest distance from the user's right shoulder to the right side of the headphones. Additionally, a sensor worn near the base of the head is used to detect the rotational direction of the head (right-handed turning or left-handed turning as viewed from above). The angle of cranial rotation with respect to the user's travel direction is computed on the basis of these two shortest distances and cranial rotation thus detected. The position of the sound source is corrected on the basis of the angle of cranial rotation.